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Waste Recycling

household waste

How exactly should household waste be dealt with? Including shit!

The Building RegulationsThese are the mass of regulations that cover safety, health, welfare, convenience, energy efficiency etc. in the way buildings are constructed. Not to be confused with Planning consent (which is more to do with whether you can put up the building in the first place). See more on the regulationsApproved DocumentsApproved documents (England) are detailed publications which come under the English Building Regulations. They are based on tried and tested methods of building and if you follow them you are assured of complying with the Regs. The equivalents for Scotland are the Technical Handbook, for Wales: the Approved documents (Wales), and for N.I. the Technical Bookletspart HThe Approved documents, (England) part H, deals with Drainage and waste disposal section 6 specify that space must be allocated for recycling containers.

The regulations also specify the distances for carrying waste and how far the storage should be from transport access.

Capacity

1.1 For domestic developments space should be provided for storage of containers for separated waste (i.e. waste which can be recycled is stored separately from waste which cannot) with a combined capacity of 0.25m per dwelling or such other capacity as may be agreed with the waste collection authority. Where collections are less frequent than once per week, this allowance should be increased accordingly.

No one seems to have the right containers in the right place! Whether it is waste food, old batteries or different types of plastic, there seems to be complete confusion, which is not helped by the way that different local authorities collect or recycle waste.

However, what is becoming increasingly apparent is the need for more careful design within the house for the positioning of the various waste containers. This depends on how your local council makes its collections in terms of separation of waste and frequency of collection.

The speed of (somewhat chaotic) development in the recycling sector is increasing and house design risks getting left behind somewhat, especially in terms of the allocation of space for the various types of waste. Local authorities differ enormously but many are now splitting their waste into around 20 different streams at the recycling depots and this may impact on how householders need to sort waste. However there are calls from some environmental groups to do the sorting at the kerbside as the waste enters the bin lorries. It is very hard to see which way it is going to pan out especially in terms of which items will be catered for by kerbside collection and which will be expected to be taken to a recycling centre by the householder.

Here are some of the main categories which householders almost certainly need to store on their own premises until either the bin lorry comes or they take them to the council recycling centre. In many cases the storage will need to be covered from rain and in some it will need to be a leak-proof container. Different councils are experimenting with a huge array of containers and wheelie bins.

The tetrapack type containers are in a class of their own due to the peculiar resistance that the manufacturers seem to have put up against sensible recycling. These containers are made up of three main materials: paper, polythene liner, aluminium foil liner. These can all be quite easily recycled by a very simple process of soaking the things (basically in a big tub of water) to separate the three components. This needs to be done at a proper facility and considering the time that tetrapacks have been around there has been little progress in making this happen. Some local authorities have tetrapak containers in their recycling centres and these containers get emptied regularly by a lorry with a suction hose and then taken for recycling. The peculiar design of these containers incorporates a ‘post box’ where you stuff the tetrapaks through a small slot. Given that visiting the recycling depot by car very often is not a good idea in terms of car fuel then one has to save up huge numbers of small packages of (smelly) tetrapaks in order to get them ‘posted’ into the container.

in a shed or unheated area or utility room – for stuff that needs keeping sheltered but you don’t want in the bins or kitchen

The local authority recycling facilities available at any particular post code are on the Recyclenow web site.

waste water treatment

The outline of why human waste may be better treated locally rather than regionally points towards the use of composting toilets in conjunction with grey waterThis is the waste water that comes from the baths, basins, showers and washing machines. Kitchen sink water is known as black water. see Recycling grey water treatment on site. As there is no water used to flush composting toilets the only waste water is grey water (dirty washing water from washing machines, sinks showers etc.) which is not particularly polluted and can be handled in four main ways.

If space around the dwelling is very plentiful then grey water can be dispersed into the ground via a leech line, soakaway or it can be run into a constructed wetland.

If space is very limited then an aerator unit will be needed to help with the BOD (biological oxygen demand) before water goes into a leech line.

If somewhere between these two there is a moderate amount of space, say a large garden, then a reed bed might be appropriate.

If the final effluent is of sufficiently high quality then it may be usable for watering gardens, washing cars etc.

With existing houses where an existing septic tank is present but which is putting out an effluent which is below standard then a reed bed may be a way of providing tertiary treatment.

Getting good expert advice on the design of these systems is most important. Over the last few decades designs have been refined and improved and there is now a large body of knowledge on the subject.

Some of the questions to consider are as follows:

How many people will it need to serve? This will determine the size.

Can it be a gravity system or will pumping be required? Pumps can be expensive to buy, run and maintain.

Where will the outflow eventually go?. Is there any risk of pollution to a watercourse if the system goes wrong?

Do you want to reuse the water in some way?

You may have to obtain discharge consent. The Environment Agency contact numbers can be found here

Very often it is possible to recycle or reuse building materials. This may take several forms:

re-using materials from a previous building on the site. Examples may include:

hardcore derived from masonry

Hardcore is typically used for bedding under drives, parking areas etc. but it is important to make sure it doesn’t contain deleterious materials or contaminants. See the Building Regulations Approved Document, Part CThe Approved documents, (England) part C, deals with Site preparation and resistance to contaminants (C1) and Resistance to Moisture (C2).

walling stone

roof tiles and slates

windows and doors (this may require careful design for their incorporation)

timber structural members

plumbing such as tanks, taps, cylinders, valves etc (providing they are tested)

electric cable and fittings (provided they are tested)

guttering

buying in reusable materials. This may be desirable / necessary when materials must match up with part of an existing building. See the section on suppliers

composting toilets

To flush or not to flush

Maybe there should be a huge move towards composting toilets, Many parts of the world accept them as standard. They are now covered by the Building Regulations part GThe Approved documents, (England) part G, deals with Sanitation, hot water safety and water efficiency.

One frequently hears the observation about how crazy it is to collect rain water in reservoirs, purify it up to drinking standard, and then use it to flush toilets. The water then has to be removed from the sewage at the sewage works and cleaned up again. This part of the process frequently goes wrong and pollutes the river or shoreline where it is dumped.

Chemical pollution

The flow of nitrates, phosphates and potassium (in the form of fertilizer) and humus (in the form of peat for gardens) into and out of houses represents a huge cost to the environment, particularly the mining, processing and transport of them and the eventual dumping of them into rivers and the sea. (in case you are not convinced of sewage dumping problems in rivers and at sea check out the Surfers Against Sewage website)

Microfibres

Along with the chemical pollution from toilets there is the issue of microfibres. Recent research has shown what a huge amount of minute plastic fibres are released after a typical washing machine cycle. Quite typically several hundred thousand fibres will go down the drain and end up in rivers and the sea. These fibres can then enter the food chain. By not using flushing toilets it makes it possible in most situations to dipose of grey water locally by means of soakaways, thus trapping microfibres at source.

The development of composting toilets

There is quite a lot of interest on the continent (particularly Sweden, Netherlands, Germany and Austria) in urine separating toilets and these are now available here. A New Scientist article makes a strong case for urine separation not only to take the strain off sewage works but also to return the valuable fertilizer chemicals like nitrogen and phosphates to the land.

The Bill Gates foundation has recently put $42 million into a project over several years to develop a toilet that doesn’t need water, mains power or sewerage and that will cost next to nothing to run. One strong contender is the Nano Membrane Toilet finalist for Cleantech, being developed at Cranfield University.

The whole problem can be addressed by the use of composting toilets and on-site grey water treatment which keep the nutrients and humus for the garden. This also results in a 30% reduction in use of water (for flushing toilets).

Financial savings

As a bonus, this results in considerably lower water bills because the sewage element of your water bill is normally based on your water usage. So if you reduce your water usage by 30% (because a composting toilet uses no water) and then get rid of paying for the sewage element (because you are not connected to mains drainage) then your water bill is reduced to a third of what it might normally be. Costings can vary a lot depending where you live in the country.

Remember that water companies charge roughly the same for sewage treatment as they do for supplying water. (water in = water out) so for every cubic metre of water you use, you will produce a cubic metre of sewage (approximately).

A typical house (with normal flush toilets) uses about 150 litres/day/person which equals 55 cubic metres (that’s 55 tonnes) of water per year per person. Assuming the cost of about £1.40/cubic metre (including standing charges) then this would cost about £77. per person each year. Getting rid of a flush toilet reduces the water usage from 150 litres down to 100 litres per day per person.

The cost of handling the sewage (per person) would be roughly the same at £77. (for some reason they charge roughly the same for supplying pure water and for handling sewage)

Total cost about £154 per year per person. And water and sewerage prices are rising steeply at present!

If you remove 30% of the water cost (flushing) and all of the sewerage cost (because you are not connected to main drainage) the total bill is £46/person/year for the water and zero for the sewage and this makes a saving of £108/person/per year. So a 4 person household would save about £432/year. This is fairly handsome reward for the extra initial cost and the (maybe) 2 hours per year spent servicing the toilet. Added to that are all the environmental advantages of cleaner rivers, streams and beaches and the retention of fertilizers in the ground.

Composting toilets tend to be of two types

very low flush type

waterless

The advantage with the very low flush type (such as the Aquatron) is that the waste can be transported horizontally through the house via pipework whereas with the waterless type it has to drop vertically. This helps if there is a problem with vertical alignment between bathrooms and composting area. The drawback is that the flushing water (which is black water) has to be dealt with somewhere on site if there is no main drainage connection and this is a bit more difficult than dealing with grey water.

Waterless toilets

There are six good reasons for using waterless composting toilets

No water is wasted in flushing and hence there is no need for the complex process of separating solids from water at a sewage works. With normal toilets, about a third of the household’s water consumption goes on flushing.

There is no chance of sewage entering rivers. It is not unusual for sewage companies to dump raw sewage into rivers when sewage works get overwhelmed during periods of flooding.

Toxic chemicals cannot get through to rivers (it is estimated about 20% of male fish in UK rivers have been feminised by absorbing hormones left over from contraceptive pills)

Fertilizer is not lost to rivers and the sea. It can be used locally. This mainly applies to nitrates.

There are no smells in the bathroom because a fan keeps the toilet under negative pressure.

The fact that human waste does not get mixed with grey water means that the grey water is easy to deal with on site by using a reed bed or leech line

Points 2-5 also apply to some extent to very low flush types.

There are five possible arguments against their use, depending on which particular design is used.

They may take up potentially valuable building space (maybe about 4 sq. m. for a Clivus)

They may be more expensive than normal loos

They may use electric power

They may partially dictate the layout of the building (in the case of such as the Clivus)

They usually need some degree of maintenance

Waterless composting toilets are basically of two types

those which have no mechanical or electrical assistance, relying on one or two large plastic containers on the floor beneath them in which the waste slowly breaks down over a few years. A slight variant of this is the waterless evaporating toilet such as the Woo Woo which uses radiant heat from the sun to create air movement and evaporation.

those which have electric heaters and stirrers which greatly speed up the process. They usually have a small container built in to the base so they can be situated almost anywhere where a vent pipe can be fitted. They may have removable plastic bags which biodegrade.

The first type uses no energy (except for a tiny fan – maybe 4 watts – which extracts air up a vent pipe to prevent smells). They produce a compost which is similar to peat and can be spread on the garden (but not onto growing vegetables). Access is needed to a cellar or space below the bathroom. They were originally developed in Sweden for summer houses where it was environmentally undesirable to blast holes through mountains for sewera municipal drain or a drain serving more than one property pipes. Since then they have been developed to a high standard with various sizes available. Examples are the Clivus Multrum and the Envirolet (waterless remote). The second type do tend to consume rather a lot of electricity.

Due to the composting toilet market in the UK being so under-developed the Clivus is not available for the domestic market here and this has led some self-builders to construct their own based on the original Clivus design as found in the books ‘The Toilet Papers” and ‘Sanitation without water’

The picture shows a Clivus ‘clone’ being built of 19mm BCX plywood (which then has a substantial surrounding structural softwood frame). The inside is lined with a thick layer of GRPglass reinforced plastic, also commonly known as fibre glass similar to that used in boat construction. A 4 Watt extract fan keeps air moving in through the seat area and out of a fluepipe to conduct gas, typically ventilation air or boiler exhaust. see Flue on the roof (similar to a normal SVPsoil and vent pipe). The bowl and drop pipe are made using the Swedish Separett urine-separation kit mounted on a vertical section of 300mm plastic land drain.

1 comment to Waste Recycling

Separett Villa composting toilets are now regularly used in self-build homes and other eco-friendly homes. They have many advantages over the types discussed here, especially as they take up no more space than a WC and are also economical to buy.
This is the way forward for toilets in this country. See http://www.ecotoilets.co.uk for more information